In order to meet wireless data traffic demands that have increased after 4G communication system commercialization, efforts to develop an improved 5G communication system or a pre-5G communication system have been made. For this reason, the 5G communication system or the pre-5G communication system is called a beyond 4G network communication system or a post LTE system. In order to achieve a high data transmission rate, the implementation of the 5G communication system in a mmWave band (for example, 60 GHz band) has been considered. In the 5G communication system, technologies, such as beamforming, massive MIMO, Full Dimensional MIMO (FD-MIMO), array antenna, analog beam-forming, and large scale antenna are discussed to mitigate a propagation path loss in the mm Wave band and to increase a propagation transmission distance. Further, the 5G communication system has developed technologies, such as an evolved small cell, an advanced small cell, a cloud radio access network (RAN), an ultra-dense network, device to device communication (D2D), a wireless backhaul, a moving network, cooperative communication, coordinated multi-points (CoMP), and received interference cancellation to improve the system network. In addition, the 5G system has developed advanced coding modulation (ACM) schemes, such as hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC), and advanced access technologies, such as filter bank multi carrier (FBMC), non orthogonal multiple access (NOMA), and sparse code multiple access (SCMA).
Meanwhile, the Internet has been evolved to the Internet of Things (IoT) network that exchanges and processes information between distributed components, such as objects and the like, in a human-oriented connection network in which humans generate and consume information. Also, the Internet of Everything (IoE) technology implemented by coupling the IoT technology and a big data processing technology through a connection with a cloud server or the like. In order to implement IoT, technical factors, such as a sensing technique, wired/wireless communication, network infrastructure, service interface technology, and security technology are required, and thus, research has been conducted on technologies such as a sensor network, machine to machine (M2M), machine type communication (MTC), and the like for a connection between objects. In an IoT environment, through the collection and analysis of data generated from connected objects, an intelligent Internet technology (IT) service to create a new value for the human's life may be provided. IoT may be applied to fields, such as a smart home, smart building, smart city, smart car or connected car, smart grid, health care, smart home appliance, or high-tech medical service, through the convergence of the conventional Information technology (IT) and various industries.
Accordingly, various attempts to apply the 5G communication to the IoT network are made. For example, the 5G communication technology, such as a sensor network, a machine to machine (M2M), a machine type communication (MTC), or the like, is embodied by beamforming, MIMO, and array antenna scheme, or the like. The application of a cloud RAN as the big data processing technology may be an example of the convergence of the 5G technology and the IoT technology.
From the early stage of providing voice-oriented services, a mobile communication system has evolved into a high-speed, high-quality wireless packet data communication system to provide data and multimedia services. To this end, various standardization organizations such as 3GPP, 3GPP2, IEEE, and the like have been working on the standardization of the 3rd evolved mobile communication system to which a multiple access scheme that uses a multi-carrier is applied. Recently, various mobile communication standards such as long term evolution (LTE) of 3GPP, ultra mobile broadband (UMB) of 3GPP2, 802.16m of IEEE, and the like have been developed to support a high-speed and high-quality wireless packet data transmission service based on the multi-access scheme using a multi-carrier.
The existing 3G evolved mobile communication system, such as LTE, UMB, 802.16m, and the like, is based on a multi-carrier multiple access scheme, may apply multiple input multiple output (MIMO) to improve the transmission efficiency, and may use various technologies, such as beam-forming, an adaptive modulation and coding (AMC) method, a channel sensitive scheduling method, and the like. The various technologies may enhance the transmission efficiency and improve the system throughput through a method of concentrating a transmission power that is transmitted from multiple antennas or adjusting an amount of transmitted data based on a channel quality or the like, and selectively transmitting data to a user having a good channel quality, or the like.
Most of those schemes are operated based on channel status information of a channel between an evolved node B (eNB) (or Base station (BS)) and a user equipment (UE) (or a Mobile Station (MS)), and thus, the eNB or the UE may need to measure a channel status between the eNB and the UE. In this instance, a channel status indication reference signal (CSI-RS) is used. The eNB indicates a downlink transmission and uplink reception device located in a predetermined place, and a single eNB performs a transmission/reception in association with a plurality of cells. In a single mobile communication system, a plurality of eNBs are geographically distributed, and each eNB performs a transmission/reception in association with a plurality of cells.
The existing 3rd and 4th mobile communication system, such as, LTE, LTE-A, or the like, utilizes the MIMO technology that executes transmission using a plurality of transmitting and receiving antennas to improve the data transmission rate and the system throughput. The MIMO technology utilizes a plurality of transmitting and receiving antennas in order to spatially separate a plurality of information streams when the information streams are transmitted. Transmitting the plurality of information streams to be spatially separated is referred to as spatial multiplexing. Generally, the number of information streams to which spatial multiplexing is to be applied may vary based on the number of antennas included in a transmitter and a receiver. Generally, the number of information streams to which spatial multiplexing is to be applied is referred to as a rank of a corresponding transmission. In the case of the MIMO technology supported in the standards up to LTE/LTE-A Release 11, spatial multiplexing with respect to the case in which the number of transmission antennas and the number of reception antennas are respectively 8, is supported, and a rank is supported up to 8.
There is a desire for a method of preventing a space from being wasted excessively in a predetermined direction in a mobile communication system that uses a multi-antenna.